package demo1;

import java.util.List;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 98152
 * Date: 2024-07-08
 * Time: 14:37
 */
public class MySingleList implements IList{
    static class ListNode {
        public int val;
        public ListNode next;

        public ListNode(int val) {
            this.val = val;
        }
    }
    public ListNode head;

    public void creatList() {
        ListNode node1 = new ListNode(0);
        ListNode node2 = new ListNode(1);
        ListNode node3 = new ListNode(2);
        ListNode node4 = new ListNode(3);

        node1.next = node2;
        node2.next = node3;
        node3.next = node4;
        head = node1;
    }

    @Override
    public void display() {
        ListNode cur = head;
        while (cur != null) {
            System.out.print(cur.val+" ");
            cur = cur.next;
        }
        System.out.println();
    }

    @Override
    public void addFirst(int data) {
        ListNode node = new ListNode(data);
        node.next = head;
        head = node;
    }

    @Override
    public void addLast(int data) {
        ListNode node = new ListNode(data);
        if(head == null) {
            head = node;
            return;
        }
        //找尾
        ListNode cur = head;
        while(cur.next != null) {
            cur = cur.next;
        }
        cur.next = node;
    }

    @Override
    public void addIndex(int index, int data) {
        if(index < 0 || index > size()) {
            System.out.println("index位置不合法！");
            return;
        }
        if(index == 0) {
            addFirst(data);
            return;
        }
        if(index == size()){
            addLast(data);
            return;
        }
        ListNode node = new ListNode(data);
        ListNode cur = head;
        for (int i = 0; i < index-1; i++) {
            cur = cur.next;
        }
        node.next = cur.next;
        cur.next = node;
    }

    @Override
    public boolean contains(int key) {
        ListNode cur = head;
        while(cur != null) {
            if(cur.val == key) {
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    @Override
    public void remove(int key) {
        if(head == null) {
            return;
        }
        if(head.val == key) {
            head = head.next;
            return;
        }
        ListNode pre = head;
        while(pre.next != null) {
            if(pre.next.val == key) {
                ListNode del = pre.next;
                pre.next =del.next;
                return;
            }
            pre = pre.next;
        }
    }


    @Override
    public void removeAllKey(int key) {
        if(head == null) {
            return;
        }
        ListNode pre = head;
        ListNode cur = head.next;
        while(cur != null) {
            if(cur.val == key) {
                pre.next = cur.next;
            }else {
                pre = cur;
            }
            cur = cur.next;
        }
        if(head.val == key) {
            head = head.next;
        }
    }

    @Override
    public int size() {
        int len = 0;
        ListNode cur = head;
        while(cur != null) {
            cur = cur.next;
            len++;
        }
        return len;
    }

    @Override
    public void clear() {
        head = null;
    }

    public ListNode partition(int x) {
        // write code here
        if(head == null) {
            return null;
        }
        ListNode ss = null;
        ListNode se = null;
        ListNode bs = null;
        ListNode be = null;
        ListNode cur = head;
        while(cur != null) {
            if(cur.val < x) {
                if(ss == null) {
                    ss = se = cur;
                }else {
                    se.next = cur;
                    se = cur;
                }
            }else {
                if(bs == null) {
                    bs = be = cur;
                }else {
                    be.next = cur;
                    be = cur;
                }
            }
            cur = cur.next;
        }
        se.next = bs;
        be.next = null;
        return ss;
    }
}
